This application claims priority from Korean Patent Application No. 2002-47200, filed on Aug. 9, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a method for measuring states of an object, and more particularly, to a method and apparatus for extracting three-dimensional data of an object using an electron microscope.
2. Description of the Related Art
Electron microscopes, particularly, scanning electron microscopes (hereinafter, referred to as xe2x80x98SEMxe2x80x99) are apparatuses which have been utilized in various technical fields including the semiconductor industries, medical science, biology, etc. The scanning electron microscopes frequently are required over various industry fields, but most SEM equipments have many problems due to their complicated operation methods and difficult maintenance and repair work. Therefore, the utilization rate of the SEM equipments is very low.
In particular, SEMs capable of measuring an object while directly observing a two-dimensional structure of the object are widely used. In this case, raw data acquired with an SEM is then converted into three-dimensional data, and general surface quantification parameters are two-dimensional data. However, in many situations, it is necessary to perform a three-dimensional measure of objects by quantifying various types of three-dimensional parameters with three-dimensional data in order to three-dimensionally observe the objects. As such, it may be possible to measure lengths, diameters, and angles of structures on cell surfaces, sizes and distances of organellas, etc. However, such SEM equipment has not yet been developed.
In images observed by a conventional SEM, it is possible to determine the interrelation of the structures qualitively. The conventional SEM processes the images analogically and uses only information from a one-axis when obtaining images for analysis. Accordingly, it is difficult to obtain a precise measuring result. In addition, it is practically impossible to measure three-dimensional structures using the conventional SEM. For this reason, there is a need for a method and apparatus for measuring a three-dimensional structure using an electron microscope, so that the interrelation of structures can be analyzed quantitatively through images converted to three-dimensional data.
The present invention provides a method and apparatus for extracting three-dimensional data of an object, using an electron microscope which processes images digitally, differently from conventional SEMs, and measures a three-dimensional structure using information obtained from three-axis directions, differently from conventional methods which create images using only information obtained from an one-axis direction.
According to an aspect of the present invention, there is provided a method for extracting three-dimensional data of an object using an electron microscope, the method comprising: obtaining two-dimensional coordinates by respectively projecting the object on a plane perpendicular to an X-axis, on a plane perpendicular to a Y-axis, and on a plane making an angle of 45 degrees from a Z-axis with a Y-Z plane, in an XYZ coordinate system; in portions where three images including the two-dimensional coordinates overlapped, obtaining data of a pixel on a base images among the three images, obtaining data of corresponding pixels of the pixel on the base image to left and right images of the base image, and calculating a disparity on the basis of the data; and extracting three-dimensional depth information of the object using the obtained disparity, the three-dimensional depth information representing a relative distance of the object, and extracting a three-dimensional coordinate on each pixel to determine a three-dimensional location of the object.
According to another aspect of the present invention, there is provided an apparatus for extracting three-dimensional data of an object using an electron microscope, the apparatus comprising: sensors which sense two-dimensional coordinates obtained by respectively projecting the object respectively on a plane perpendicular to an X-axis, a plane perpendicular to a Y-axis, and a plane making an angle of 45 degrees from a Z-axis with a Y-Z plane; a disparity determination unit which, in respective overlapped portions of three images including the two-dimensional coordinates respectively sensed by the sensors, obtains data of corresponding pixels of a pixel on a base image to left and right images of the base image, and calculates a disparity on the basis of the data; and three-dimensional data extraction unit which extracts three-dimensional depth information of the object using the disparity determined by the disparity determination unit, the three-dimensional depth information representing a relative distance of the object, and extracts a three-dimensional coordinate on each pixel to determine a three-dimensional location of the object.